Phytochemistry, antioxidant activity, and sunscreen efficacy of hydroethanolic extract of Cabernet Sauvignon grape pomace (Vitis vinifera L.)

Grape pomace maintains 20 – 30% of polyphenols in peels and 60 – 70% in seeds after winemaking [1]_. In this context, it is of interest using grape marc in cosmetic formulations containing UV filters aiming to promote positive interactions among these ingredients, and to achieve differentiated UV protection to the skin [2].

In this work, the hydroethanolic extract of grape pomace Cabernet Sauvignon (V. vinifera L.) was obtained by percolation. Polyphenol content, expressed as gallic acid equivalents (GAE, dry weight), was determined on the crude extract and the chloroform, ethyl acetate and aqueous fractions: 141.11 mg GAE/g, 93.4 mg GAE/g, 504.96 mg GAE/g and 134.06 mg GAE/g, respectively [3]. The antiradical efficiency towards DPPH of formulations containing 1 mg/ml of the extract showed increments up to 46% [4], although,^.the UV filters, butyl methoxydibenzoyl methane, ethylhexyl methoxycinnamate and ethylhexyl dimethyl PABA had no significant influence on this effect. On the other hand, the determination of sunscreens efficacy and photostability by diffuse reflectance spectrophotometry of samples containing the residue (10% w/w), suggested a synergism between the active and bioactive compounds, as showed by an increment of the sun protection factor (SPF) by 76%. After 2h of artificial solar irradiation all samples displayed SPF reduction, however, formulations combining filters and the natural compound showed SPF values up to 16% higher than the extract-free control. According to these results, the grape pomace hydroethanolic extract has a promising multifunctional and innovative potential for cosmetic purposes.

Acknowledgements: National Counsel of Technological and Scientific Development (CNPq) for financial support.

Keywords: Sunscreen, sun protection factor (SPF), UV filter, Vitis vinifera L., grape pomace.

References:

[1] Monrad JK. Subcritical solvent extraction of anthocyanins from dried red grape pomace. J Agric Food Chem 2010; 58: 2862 – 2868

[2] Stevanato R, Bertelle M, Fabris S. Photoprotective characteristics of natural antioxidant polyphenols. Regul Toxicol Pharmacol 2014; 69: 71 – 77

[3] Renaud S, Lorgeril M. Wine, alcohol, platelets, and the French paradox for coronary heart disease. The Lancet 1992; 339: 1523 – 1526

[4] Nichols JA, Katiyar SK. Skin photoprotection by natural polyphenols: antiinflammatory, antioxidant and DNA repair mechanisms. Arch Dermatol Res 2010; 302: 71 – 83